1. Field of the Invention
The present invention relates to an apparatus and method for cleaning sewers and catch basins, and, more specifically, to a mobile sewer and catch basin cleaner which continuously filters reclaimed water so that such water may be reused in the cleaning process.
2. Description of the Prior Art
Certain types of mobile catch basin and sewer pipe cleaners are known in the art. For example, in Shaddock, U.S. Pat. No. 3,658,589, entitled "Catch Basin and Sewer Pipe Cleaner", water stored in a clean water reservoir in the vehicle is injected at high pressure into sewer laterals (or sewer lines). The water is discharged through nozzles which backwash the dislodged debris into a manhole. A vacuum system then pneumatically conveys the debris-laden water into a debris collection chamber. However, the Shaddock reference does not teach the reuse of reclaimed water in the cleaning process and the water reservoir disclosed therein must be frequently refilled with clean water to continue the cleaning operation.
Some sewer cleaning systems employ centrifugal cleaning methods to filter and recycle the reclaimed water so that it may be reused in the sewer cleaning operation. In Flynn, et al., U.S. Pat. No. 4,134,174, entitled "Sewer and Catch Basin Cleaner", such a recycling system is disclosed. After the coarser debris material is filtered out of the contaminated water by the forces of gravity, the contaminated water is then filtered through a cylindrical screen. This water is then further cleaned through a centrifugal particle separator before being introduced back into the vehicle's clean water reservoir. This system has several disadvantages, however. First, introducing the reclaimed water back into the clean water reservoir raises the substantial likelihood that any debris remaining in the reclaimed water will corrode the reservoir. Further, such contaminated water may unnecessarily create a potential health hazard to persons, such as system operators and mechanics, who come into contact with the clean water reservoir.
Second, the cylindrical screen in Flynn is cleaned by an air-blowing system to attempt to remove any obstructions in the screen pores. However, the screen is wholly submerged in the debris-laden water and, consequently, such an air cleaning system is highly inefficient because it must displace not only all of the contaminated water surrounding the screen, but also the particulate matter clinging to the screen in order to clean the screen. Additionally, this air cleaning system has substantial difficulty cleaning fine-mesh screen media, and therefore, typically can only be applied to screens with larger openings, such as the 790 to 5550 micron screens suggested in the Flynn disclosure. Using such larger screens obviously results in a greater amount of particulate matter not being filtered out.
Third, centrifugal cleaning systems disclosed in the prior art, including that described in Flynn, do not work effectively under all conditions. For example, sufficiently greasy water will clog the underflow of the centrifuge, thereby rendering the centrifugal cleaning system inoperative. Moreover, such centrifugal systems typically are ineffective when attempting to filter water having a large concentration of particulate matter. Last, centrifugal separation cannot filter out particulate matter which is less dense than water.
In contrast, as discussed below, it is a principal object of the present invention to provide a novel apparatus and process for recycling reclaimed water into the cleaning process without the foregoing disadvantages of the prior art.
Another object of the present invention is to provide an improved process for recycling the water reclaimed from a sewer or catch basin for use in further sewer or catch basin cleaning operations.
It is a further object of the present invention to provide such a process which works effectively under all the conditions routinely encountered when cleaning sewers and catch basins.
It is yet a further object of the present invention to provide an apparatus and process which permits the operator to remain at the cleaning site throughout the cleaning operation and without the need for continually refilling the clean water reservoir.
These and other objects of the present invention are presented by way of illustration and not limitation, and are fully described with reference to the drawings and the following detailed description of a preferred embodiment of the present invention.